The poultry industry generally involves the incubation, hatching and feeding of millions of birds each week in the United States alone. A single hatchery can handle more than 500,000 chicks per week. Improvements in the various stages of development of commercial poultry can translate into significant cost savings and efficiencies. For example, improved hatching yields, shortened periods for feeding, and increased size of poultry produced can provide substantially increased profits.
Meat production by domestic animals is inherently inefficient and this is mainly reflected in higher costs during the growth and the finishing phases of production. For example, commercial production of poultry in the major poultry-food importing countries (for example, Israel) is several times more expensive than in poultry-food exporting countries. This is due to the fact that in any system of poultry meat production, feed costs form up to 70% of total costs. Therefore, increasing the speed and biological efficiency of muscle growth would both increase the economic efficiency of meat production, and its improved biological efficiency would also be expected to produce more meat and less fat at any point in time during production. This alteration in the composition of weight gain in meat producing animals would enhance the nutritional value of the end product, an issue of increasing importance particularly in the United States.
Muscle growth is a function of protein accretion and cell proliferation. Muscle protein accretion is a function of protein synthesis and degradation, and the balance between protein synthesis and degradation determines the net gain or loss of muscle mass. Although protein accretion is an important aspect of muscle growth, it is limited within the existing cellular framework. Myogenic cell proliferation and differentiation during pre- and postnatal life establish this cellular framework and set limits on postnatal muscle growth.
Muscle growth in poultry can be influenced by local and circulating growth factors and hormones. Methods known in the art can manipulate levels of these factors in vivo by nutritional, genetic and environmental manipulations. Alternatively, methods known in the art alter these factors by administering growth hormones to the poultry to increase muscle growth. However, such administration requires regulatory approval and is not generally preferred by the consuming public.
The present invention represents an advance in the art of increasing meat production by poultry. It is known that exposure of birds to certain types of light after hatching can influence several characteristics of the birds. The present invention describes the exposure of eggs to certain wavelengths of light. Unexpectedly, such exposure caused increases in performance characteristics, and these characteristics manifested themselves later in the life of the birds. Moreover, the characteristics were predominant in females, and generally not in males.
The present invention provides methods for exposing an embryo to light. The method includes exposing an egg, preferably a chicken egg or a turkey egg, to a monochromatic light for an intermittent photoperiod that includes a light period and dark period. The light period and the dark period may each independently be at least about 3 minutes, at least about 15 minutes, preferably, about 3 minutes to about 15 minutes. The monochromatic light may include a peak wavelength of at least about 500 nanometers (nm) to no greater than about 590 nm, preferably, at least about 550 nm to no greater than about 570 nm, most preferably, about 560 nm. Preferably, the monochromatic light has an intensity of at least about 0.001 watts/m2 to no greater than about 0.2 watts/m2.
The present invention also provides a method for increasing a bird""s weight. The method includes exposing an egg, preferably a chicken egg or a turkey egg, to a monochromatic light for a photoperiod, and hatching the egg, wherein the bird, preferably a hen, that hatches from the egg has a greater weight at about 28 days after hatching compared to a bird that hatches from an egg not exposed to the monochromatic light. The photoperiod may be an intermittent photoperiod that includes a light period and a dark photoperiod. The light period and the dark period may each independently be at least about 3 minutes, at least about 15 minutes, preferably, about 3 minutes to about 15 minutes. The monochromatic light may include a peak wavelength of at least about 500 nm to no greater than about 590 nm, preferably, at least about 550 nm to no greater than about 570 nm, most preferably, about 560 nm. Preferably, the monochromatic light has an intensity of at least about 0.001 watts/m2 to no greater than about 0.2 watts/m2.
Also provided by the present invention is a method for increasing muscle weight in a bird, preferably a hen. The method includes exposing an egg to a monochromatic light for a photoperiod, and hatching the egg, wherein the bird that hatches from the egg has greater muscle weight at about 28 days after hatching compared to a bird that hatches from an egg not exposed to the monochromatic light. Preferably, the muscle is breast muscle. The photoperiod may be an intermittent photoperiod that includes a light period and a dark photoperiod. The light period and the dark period may each independently be at least about 3 minutes, at least about 15 minutes, preferably, about 3 minutes to about 15 minutes. The monochromatic light may include a peak wavelength of at least about 500 nm to no greater than about 590 nm, preferably, at least about 550 nm to no greater than about 570 nm, most preferably, about 560 nm. Preferably, the monochromatic light has an intensity of at least about 0.001 watts/m2 to no greater than about 0.2 watts/m2.
The present invention further provides a method for decreasing a mortality rate of a bird, preferably a hen. The method includes exposing an egg, preferably a chicken egg or a turkey egg, to a monochromatic light for a photoperiod, and hatching the egg, wherein the mortality rate of a bird that hatches from the egg has a lower mortality rate compared to a bird that hatches from an egg not exposed to the monochromatic light. The photoperiod may be an intermittent photoperiod that includes a light period and a dark photoperiod. The light period and the dark period may each independently be at least about 3 minutes, at least about 15 minutes, preferably, about 3 minutes to about 15 minutes. The monochromatic light may include a peak wavelength of at least about 500 nm to no greater than about 590 nm, preferably, at least about 550 nm to no greater than about 570 nm, most preferably, about 560 nm. Preferably, the monochromatic light has an intensity of at least about 0.001 watts/m2 to no greater than about 0.2 watts/m2.